It's possible to obtain a visa on arrival for Nigeria to enter at the Seme border crossing.

An approval letter must be acquired first before arriving at the border. To obtain the approval letter, either:

1. Apply at Nigeria Immigration Service - Visa on Arrival. There are some reports that the Immigration service did not respond to applications.
2. Apply through a 3rd party agent. The cost was 200.00 USD from Destinali. The approval letter is issued with 48 hours.

Arrive at Seme with printed copies of the approval letter. Note, there are two letters that look similar, and both should be printed. The Immigration Controller needs to sign/authorise this, so there may be a wait of an hour at the border.

To obtain the visa, you must be escorted by an immigration officer to Lagos airport. For Biking Over Yonder, with a motorcycle, and others, this meant the immigration officer rode pillion on the motorcycle. A return taxi fare of 25,000 NGN was required for the immigration officer to return to the Seme border crossing with paperwork completed.

At the airport, you are escorted through different offices and eventually arrive at the visa on arrival office. This is located where flight passengers disembark and arrive in the terminal, which is before passport control. In the visa on arrival office, you pay for the visa using a VISA card. Note: mastercard and cash are not accepted. Alternatively, you can pay online and present the visa payment receipt (and/or visa acknowledgement slip). Be sure to pay for visa on arrival (business) and not tourist visa, even though you may be travelling as a tourist.

This information was learnt from friends who crossed the border before me. I just followed in their footsteps. I've also added the above to wikioverland.org/Nigeria and the West Africa Travellers group on Facebook. Hope it helps!

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BikingOverYonder.com RTW